added message at top of module and removed from global

Conflicts:
	src/cmfd_data.F90
	src/fixed_source.F90
	src/global.F90
	src/tally_new.F90
changed how messages are handled

Conflicts:
	src/cmfd_execute.F90
	src/input_xml.F90
	src/string.F90
	src/tally_new.F90
	src/tracking.F90
Added comments, alphabetized declarations for #332
Switched to assumed-length characters for #332
Converted messages to string literals #332
Small fixes for #332
Fix Python 3.x incompatibility in trace test
Merge pull request #333 from bunder/develop

Fix Python 3.x incompatibility in trace test
Merge pull request #332 from smharper/tally_refactor01

Make 'message' non-global
Fix a typo in user's guide and add an entry to the RELAX NG schemata for
plots.xml.