[FEATURE][QGIS-Server] Add Web Coverage Service support : funded Ifremer

QGIS-Server already supports standards : Web Map Service (WMS version 1.3.0
and 1.1.1) and Web Feature Service (WFS version 1.0.0) and Web Feature
Service with Transaction (WFS-T).
The French Research Institute, Ifremer, would like that QGIS-Server supports
all the OGC standards.
We (3Liz) are implementing the Web Coverage Service (WCS version 1.0.0)
support in QGIS-Server.
attempt to fix http://hub.qgis.org/issues/9184
convert GDAL no data value to a value representable by data type, fixes #3840
fix warnings
german translation update and one translation string fix
[composer] Fix overview extent not being drawn on composer outputs if map is set to Rectangle preview mode
Merge pull request #1026 from anitagraser/working

attempt to fix http://hub.qgis.org/issues/9184
[composer] Make map rectangle preview text a bit more subtle
Merge pull request #1025 from rldhont/wcs

[FEATURE][QGIS-Server] Add Web Coverage Service support : funded Ifremer
[TRANSUP] Hindi by Harish

Signed-off-by: Werner Macho <werner.macho@gmail.com>
[FEATURE] fill ring digitinzing tool
Used to cut holes in polygons and automatically fill them with new
features. Attributes taken from parent feature. Feature form opens
by default. Hold Ctrl key to suppress it.