Move _HbLexer to generated sources folder

Also updates jflex_generate.sh for the new location
handlebars: add decimal support instead of integer (see https://github.com/wycats/handlebars.js/issues/472)

Conflicts:
	gen/com/dmarcotte/handlebars/parsing/_HbLexer.java
	handlebars/src/com/dmarcotte/handlebars/HbHighlighter.java
handlebars: update tokenizer spec tests

Bring HbTokenizerSpecTest back in sync with Handlebars tokenizer spec
tests ('spec/tokenizer.js')
handlebars: add support for subexpressions

See https://github.com/wycats/handlebars.js/commit/b09333db7946d20ba7dbc6d32d5496ab8295b8e1

Conflicts:
	gen/com/dmarcotte/handlebars/parsing/_HbLexer.java
	src/com/dmarcotte/handlebars/parsing/HbParsing.java
handlebars: fix error message typo
Merge pull request #95 from dmarcotte/backport

Backport recent features