Merge pull request #31 from zwelchWI/master

Update libxml++ to 2.36
added cmake version query
bumped libxml version
Merge pull request #32 from cyclus/libxml

bumped libxml version
out of source builds
cycamore build bug
Fix nightly build error; INSTALL environment variable already in use
fix bug
Fix nightly build error; INSTALL environment variable already in use
Update to handle comments