Hexagon: updated software/libraries

Hexagon has updated software/libraries.

Please see the following for full description:

http://docs.cray.com/books/S-9407-1404//S-9407-1404.pdf

http://docs.cray.com/books/S-9404-19//S-9404-19.pdf


cray-mpich 6.3.0 -> 6.3.1
cray-lgdb 2.2.4 -> 2.3.0
cce 8.2.5 -> 8.2.6
atp 1.7.1 -> 1.7.2
chapel 1.8.0 -> 1.9.0
pgi 14.2.0 -> 14.3.0
re-issue of cray-gcc 4.8.0, 4.8.1 and 4.8.2