Merge pull request #8 from Samrat-Revagade/master

Hint bit updates screw up pg_rewind
Correct whitespaces in code

This makes the code a bit cleaner.
Remove commented block of code

This code might have been used only for some debugging.
Improve output message when rewind begins

Patch by Samrat-Revagade
Ensure that rewind is done from latest common checkpoint

This fixes a bug where the rewind could begin at the point of WAL
diversion between the source folder and the folder to be rewinded
and not the last common checkpoint.

Patch by Samrat-Revagade, with some additional comment by me.
Refactor regression tests of pg_rewind

All the modes of tests are refactored and combined into a single script
for clarity, script that can be invocated with a simple "make check"
command, making it transparent to user.
Mention in README how to launch regression tests
Add expected test suite output

This was forgotten by last commit because of .gitignore that forbid
its inclusion.
Prepare pg_rewind for 9.4 development
Fix GIN split record parsing for 9.4.
Make mandatory the use of data checksums

A sanity check based on the target's control file data is done with
its data checksum algorithm. This is to prevent data corruption that
could occur because of hint bits.
Make mandatory the use of wal_log_hintbits when rewinding

Either data checksums or WAL logging of hint bits needs to be activated
on server.
Add URL for bug report in --help

As the project is on github, bug reports should be sent their as well.
Rename wal_log_hintbits to wal_log_hints
Fix code due to rework of tuple freeze in core Postgres

Some compilation errors have been introduced by 3b97e68 in core postgres.
This commit just makes sure that things are not broken anymore.
Call pg_rewind as if in PATH in test.sh

This is to be consistent with the other calls.