Return self from PG::Result#check instead of nil. This allowes to stack method calls.
Add PG::Connection#copy_data as a convenience method.
merge tip
Remove copy examples in favour of #copy_data
Add #copy_data case for non copy statement
Wrap all PQsend* functions to be called without GVL.

These functions could trigger the notice callback when some notice is yet
in the buffer. The notice callback needs to be called without GVL since it
always reaquires the GLV. This fixes issue #171.
Wrap PQisBusy to be called without GVL. It could trigger the notice callback.
Fix examples of conn#copy_data and improve the documentation.
Bump VERSION to 0.16.1 and prepare History.rdoc for release.
Improve Connection#copy_data:
- ensure and verify a clean exec status for each test case
- add error PG::NotAllCopyDataRetrieved and a spec for this case
- fix input/output naming in the specs
- use ArgumentError instead of PG::Error in case of non-COPY statement
verify_clean_exec_status itself should leave a clean status.
Add change of PG::Result#check to History.rdoc.
Bump minor version
Add the Gemfile to the list of files that don't have to be on the Manifest.
Added signature for changeset eed93df350a6
Added tag v0.17.0 for changeset 30da9c169efc