add support for rails 2.3
limit diffs for v2.3 to v3.0, including UI
max compare for v3.0+ increased
escape backslash in heredoc so it's included in the resulting string
Change how 2.3 apps are generated

- Ensure version number is not used as app name
- Remove randomness of secret tokens
Adjust how tags are nested
Fix JavaScript handlers, hide switch with CSS
Correctly state tag name in path
Set minimum version by what versions can be generated
Add v2.3.6+