added new compiler class
added text,var nodes, moved some stuff around
moved filter expression, excised dead code
moved for node handler
fixed handle_node absorbing errors
moved trans node
moved blocktrans node
moved include node
moved if node
moved some junk around
added compile method
renamed render_expr to cond_expr, added a bunch of docstrings
cleaned lint errors
Merge branch 'compiler-refactor' into develop
added license