weapondefs: dyndamageexp customparam

to remedy its unavailability via lua WeaponDefs
Possible fix for issue #277
Fixed the bounds issues for low FOV
increased minimum zoomed in angle further
increased minimum zoomed in angle further
Map extension default Texture Brightness lowered
Small GLSL fixes
Merge pull request #338 from dvr333/cofc_slight_bounds_loosening

Improved the COFC bounds issues, especially for low FOV
Merge pull request #337 from dvr333/buildbot_fix_for_#277

Possible fix for issue #277
Merge pull request #336 from sprunk/patch-9

weapondefs: dyndamageexp customparam
Merge pull request #339 from dvr333/map_extension_clearer_darkness

Map extension default Texture Brightness lowered, makes identifying what the extension is easier