Observable contexts.
Merge remote branch 'remotes/origin/master' into observable-context
Observable contexts are added to bound elements.
Observable Context works but somewhat buggy.
Observable context just works with limitations.

Bugs and new issues arise with modification, please use caution.
Modifications to pass unit tests.
Update .travis.yml to use PHPUnit 3.7.x
Update package.json
Update .travis.yml to test with PhantomJS
Many log output in the common test for PDO database class are removed.
The contextual menu associated with relationship is working fine as ever.

The contextual menu is seen in the Sample_form; you select anything on
“way” field and the choices of the “kind” field depends on the
selection of “way” field.
The create record and batch save mode's bugs are fixed.
Bugs about create record and batch save mode was fixed.

Now, the context-based core works, but the JS components are still
buggy. Be careful.
Fix handling of '__operation__' after commit 1e40c770a6aff7590a5092dd1ff8eb61d4580969
Fix #103 (related commit is 21995020d1cdaa5560ef4a72e3815a4b1d02e67a)
Merge remote branches 'remotes/origin/fix-converting-criteriaobject' and 'remotes/origin/fix-postonlymode-with-related-context' into observable-context
Merge branch 'observable-context'

The context based archtecture is almost finished.