Test IronPython on Travis CI
Fix bloated build matrix
Output capture and assert rewrite not work on ipy
Turn on FullFrames to use inspect.currentframe()
Make the context to return the stage itself
Finer error message for doubly begun transactions
Test doubly begun transaction error
Specialized ElementList registry.  Close #23
Specialized list mixin for Link objects  #23
Alternate fixed-width fonts for docs
Docs about core concepts
Root element's stack_top has to be 1.

Fix a bug that root element's stack_top becomes
the stack depth of the first iteration step,
not 1.
Remove unused imports
Generalize duplicated feed() calls
Raise TypeError when pool_size is missing
Merge branch 'master' of https://github.com/earthreader/libearth
IronPython string compatibility
System.IO.Stream impl that takes Python iterable
Almost fix schema_test
Fix invalid yaml