Fixed non-(current)standard usage of L(I) for Laws 4, 44, 61, 67. Error will be thrown.
Updated troubleshooting documentation to reflect the new error message for the invalid L(I) usage.
Merge remote-tracking branch 'upstream/develop' into endf66
Merge pull request #226 from nelsonag/endf66

Endf66
Started release notes for 0.5.4.
fixed mistake
Mention how to local install in documentation. Closes #247.
check for present source bank before running calculation
simplified cleanup script
remove compile from all-tests option
removed source from separate and write tags
added source present to statepoint.py and incremented version
moved source_present data to the end of meta data section of statepoint writing
Update settings.xml RELAX NG schema.
Make batches/interval sub-attribute optional in settings.rnc.
removed check variable to address @paulromano comment
formatted source_present lines as per PEP8
Merge branch 'source_interval' of github.com:mit-crpg/openmc into source_interval
removed extension from cleanup
Merge pull request #236 from mit-crpg/source_interval

More control for source bank writing