Docu update

doc/tex/formats.tex

 %Every input and output file is a collection of 2D or 3D variables
 %over an unlimited number of time steps.
 
-\section{GRIB edition 1}
+\section{GRIB}
 
 GRIB \cite{GRIB} (GRIdded Binary) is a standard format designed by the
 World Meteorological Organization (WMO) to support the efficient 
@@ -26,53 +26,61 @@ their locally defined GRIB tables available to users.
 {\CDI} does not support the full GRIB standard. The following
 data representation and level types are implemented: \\
 
-\begin{tabular}{rl}
-\textbf{Grid type} &  \\
-   0  & Latitude/longitude grid \\
-   3  & Lambert conformal grid \\
-   4  & Gaussian latitude/longitude grid \\
-  10  & Rotated latitude/longitude grid \\
-  50  & Spherical Harmonic Coefficients \\
- 192  & Icosahedral-hexagonal GME grid \\
+\begin{tabular}{|r|r|l|l|}
+\hline
+\rowcolor[gray]{.9}
+GRIB1  & GRIB2 & & \\
+\rowcolor[gray]{.9}
+ grid type &  template & GRIB\_API name & description \\
+     0  & 3.0 & regular\_ll & Regular longitude/latitude grid \\
+     3  & -- & lambert & Lambert conformal grid \\
+     4  & 3.40 & regular\_gg & Regular Gaussian longitude/latitude grid \\
+     4  & 3.40 & reduced\_gg & Reduced Gaussian longitude/latitude grid \\
+   10  & 3.1 & rotated\_ll & Rotated  longitude/latitude grid \\
+   50  & 3.50 & sh & Spherical harmonic coefficients \\
+ 192  & 3.100 & -- & Icosahedral-hexagonal GME grid \\
+  --   & 3.101 & -- & General unstructured grid \\
+\hline
 \end{tabular}
 
 
-\begin{tabular}{rl}
-\textbf{Level type} & \\
-   1  & Surface level \\
- 100  & Isobaric level \\
- 103  & Altitude above mean sea level \\
- 105  & Height above ground \\
- 107  & Sigma level \\
- 109  & Hybrid level      \\
- 110  & Layer between two hybrid levels   \\
- 111  & Depth below land surface    \\
- 112  & Layer between two depths below land surface   \\   
- 113  & Isentropic (theta) level \\
- 160  & Depth below sea level    \\
+\begin{tabular}{|r|r|l|l|}
+\hline
+\rowcolor[gray]{.9}
+GRIB1  & GRIB2 & & \\
+\rowcolor[gray]{.9}
+ level type &  level type & GRIB\_API name & description \\
+     1  &    1 & surface & Surface level \\
+   99  & --  & -- & Isobaric level in Pa \\
+ 100  & 100 & isobaricInhPa & Isobaric level in hPa \\
+ 103  & 102 & heightAboveSea & Altitude above mean sea level \\
+ 105  & 103 & heightAboveGround & Height level above ground \\
+ 107  & 104 & sigma & Sigma level \\
+ 109  & 105 & hybrid & Hybrid level      \\
+ 110  & 105 & hybridLayer & Layer between two hybrid levels   \\
+ 111  & 106 & depthBelowLand & Depth below land surface    \\
+ 112  & 106 & depthBelowLandLayer & Layer between two depths below land surface   \\   
+ 113  & 107 & theta & Isentropic (theta) level \\
+ 160  & 160 & depthBelowSea & Depth below sea level    \\
+\hline
 \end{tabular}
 
-%\begin{itemize}
-%\item   0 Latitude/longitude grid
-%\item   4 Gaussian latitude/longitude grid
-%\item  10 Rotated latitude/longitude grid
-%\item  50 Spherical Harmonic Coefficients
-%\item 192 Icosahedral-hexagonal GME grid
-%\end{itemize}
-
-%\begin{itemize}
-%\item   1 Surface level
-%\item 100 Isobaric level
-%\item 103 Altitude above mean sea level
-%\item 105 Height above ground
-%\item 109 Hybrid level     
-%\item 110 Layer between two hybrid levels  
-%\item 111 Depth below land surface   
-%\item 112 Layer between two depths below land surface     
-%\item 113 Isentropic (theta) level
-%\item 160 Depth below sea level   
-%\end{itemize}
+\subsection{GRIB edition 1}
 
+GRIB1 is implemented in {\CDI} as an internal library and enabled per default.
+The internal GRIB1 library is called CGRIBEX. This is lightweight
+version of the ECMWF GRIBEX library. CGRIBEX is written in ANSI C with a portable Fortran interface. 
+The configure option {\tt --disable-cgribex} will disable the encoding/decoding of GRIB1 records with CGRIBEX.
+
+\subsection{GRIB edition 2}
+
+GRIB2 is available in {\CDI} via the ECMWF GRIB\_API \cite{GRIBAPI}.
+GRIB\_API is an external library and not part of {\CDI}. To use GRIB2 with
+{\CDI} the GRIB\_API library must be installed before the configuration
+of the {\CDI} library. Use the configure option {\tt --with-grib\_api} to
+enable GRIB2 support. 
+
+The GRIB\_API library is also used to encode/decode GRIB1 records if the support for the CGRIBEX library is disabled.
 
 \section{NetCDF}