Don't override :session_id setting if it's being set somewhere else when
the admin starts, see: https://github.com/padrino/padrino-framework/issues/500#issuecomment-16836189
Correct fix for Slim #1431, #1434, #1435
fix #1438
Remove color monkeypatching from strings, tuck that away in separate class (RE #1438)
Merge pull request #1437 from minad/correct-slim-fix

Correct fix for Slim #1431, #1434, #1435
fix RenderDemo to use configuration of rendering/extensions
fix MarkupDemo
use hash to store template handlers
We should use `=` instead of `-` in slim.
We should use `=` instead of `-` in haml.
Merge pull request #1442 from namusyaka/slim-future

use `=` instead of `-` in slim and haml
move special code to template handlets
fix haml
detect erb properly
fix tests to use `=`, check for content_for double output
check output count, enable skipped tests
cleanup unused methods, clarify block_is_type?
disable concatenating `-` in templates for Slim and Haml, add tests for this
Merge pull request #1441 from padrino/fix-output-handlers

Fix and cleanup output handlers
cleanup template handlers