Fluidity intel build

This branch includes a number of fixes required to make fluidity build with the recent intel compilers (tested on 14.3.174). Most of the work was done by Ben Menadue at the NCI (with Steph and myself chipping in occasionally). 

Optimization flags have been updated and for the small suite of tests that I've undertaken, comparing an optimized intel build with an optimized gfortran build, we see a significant speedup (it is consistently > 30% and sometimes more). 

Most of the changes required were minor (the difficult part was spotting what changes were necessary, due to numerous compiler and internal segfaults etc).

There is a buildbot branch here: 
http://buildbot-ocean.ese.ic.ac.uk:8080/waterfall?category=fluidity-branches

Which should be green by the time you all wake up! Note that 3 separate bug reports have (or are in the process of being) sent to Intel, which should be fixed and released in 15.2... our workarounds are sufficient for now. 

Testing: make test passes all tests with the intel compilers, with and without optimization (excluding the forcing test, which is a fluidity bug, currently being fixed/examined by Jon Hill).