Add OSG env variable support
NEW: "which" utility

Mimics the SHELL command "which"
Use the which utility

to find the glexec in the PATH (if it's there)
FIX: submission is not a string

The submission['Value'] is sometimes a tuple, in the glexec case anyway, so it needs a cast to string
NEW: added options Cache and CacheHistory to tune RSSCache on
ResourceStatus helper.
Added Config and ConfigHistory to INSTALL.TXT, and added agents and
services instructions as well.
FIX: updated ConfigTemplate
save
FIX: allows dirac-admin-allow/ban-se to allow a SE on Degraded (
Degraded->Active ) and ban a SE on Probing ( Probing -> Banned ). In
practice, Active and Degraded are "usable" states anyway.
Merge pull request #1143 from sposs/fix-glexec

Fix glexec
Merge pull request #1144 from ubeda/NEW_RSSCache_from_CS

NEW: added options Cache and CacheHistory to tune RSSCache
Merge pull request #1145 from KrzysztofCiba/fix-transferDB

FIX: FTSRequest
Merge pull request #1146 from ubeda/FIX_diracSEscripts

FIX: dirac-admin-allow/ban-se with Degraded / Probing
v6r7-pre6