add support for string literals with single quotes
when scanner hits error, restore source to original state for reparse
bugfix: controller needs to parse context to render
allow '=' as a synonym for '=='
bugfix: w/ $var followed by quote, quote is incorrectly parse in template

so for this case, if we get a scanner error looking past the variable
we just ignore the error, and bypass "." and "(" checks, and return the
var. The scanner is put back into literal mode, and will reparse the quote
correctly.
refactored a bunch of tests to make them cleaner using helper function