Add back in changes for Bug #2106
Addressed bugs 2146 and 2147.
Removes depricated files get_session.php and save_session.php; both files replaced with postvar.php on previous commit.
Addressed bug 2155 for problems 100+.
Merge branch 'master' of https://github.com/rptiwari/LaitsV3.git into bstrong
Create Node disabled in inputs in coached when no node needs to be created for current vertex.
Resolved bug 2411.
Create Node disabled in inputs in coached when no node needs to be created for current vertex.
Resolved bug 2033.
disable bubbles
Fixed division/subtraction issues in calculations panel parsing.  Also, lol.
Fixed equation export issue in author mode
Updated xml code for bug 2155.
Changes to HttpAppender to use a list for post variables.
xml for isles
Merge changes by Reid and Brandon on Isle Royale
problems, isle01.xml, isle02.xml, isle03.xml .
Completed problems for physics teacher (Steve Eno).
Fixed equation export issue in author mode
Merge branch 'master' of https://github.com/rptiwari/LaitsV3.git
Make test for undefined nodes, Bug #2159.