Remove unused imports in python compute
Remove extra Scalar implementation
Make Scalar constructible
Remove dead assignment and * import
Scalar should be constructible, but empty
remove debug print statement
Merge branch 'master' into fix-double-return

Conflicts:
	blaze/compute/python.py
	blaze/expr/scalar/tests/test_scalar.py
Revert scalar construction test
Merge pull request #431 from cpcloud/raise-on-different-schema

Raise when Table has a different schema than the underlying data
README: fix typo
Merge branch 'master' of github.com:ContinuumIO/blaze
expr: getstate, setstate for Expr
datashape: Record api changed
remove debug printing code
Merge pull request #432 from mrocklin/serializability

Serialization and Records
Merge branch 'master' into fix-double-return

Conflicts:
	blaze/expr/table.py
Merge pull request #433 from mrocklin/fix-double-return

Fix double return
simplify compatibility
Merge pull request #434 from mrocklin/compatibility

simplify compatibility
expr: scalar coerce on optional types