Support for Cassandra NoSQL

Very basic but working support for Cassandra NoSQL 1.2.0. Requires
Cassandra JDBC connector 1.1.2 or later.
Supports:
- creation and using locking and log table
- changesets based on <sql> block with CQL
CORE-1252 Remove build-helper-maven-plugin from liquibase-core/pom.xml
fix CORE-1230

shutdown derby database depends on whether it is embedded or network
server
Put integration tests back into parent POM after beta1 release. Updated intellij config files
Switched to .idea dir for intellij config
Additional documentation
added support for outputting remarks for columns and tables
Fixes for running H2 and Hsql integration tests.

Set value for unquotedObjectsAreUppercased to true for H2 and Hsql.
Added new date time format for a date string with both a space and a dot.
For H2, A timestamp was getitng converted into a date string that did not match
any of the existing ones.
Implemented object quoting strategy

Cuurently, only postgres implements a form of quoting whereby mixed case object names and object names that start with numeric characters are quoted.

I added a new property for either a changelog or a changeset.
A user can choose, to keep the existing functionality for backwards compatibility, quote only reserved words or quote all object names.

This allows for a conssitent approach to quoting object names across all databases. I added suuport for seperate setting of the referenced table name and column names in a constraint as well. This allows the individual objects to be quoted if necessary.

Added precondition for checking what quoting strategy is set.
This is used for testing.

Uncommented the liquibase integration tests module in the main pom.
Without this, the integration tests wouldn't run in intellij.
Merge pull request #105 from lcmatrix/CORE-1230

fix CORE-1230
Merge pull request #107 from vorbis/patchFix

Fixes for running H2 and Hsql integration tests.
Better support for generating documentation for website
Tests fixes
Merge remote-tracking branch 'origin/master'
Merge branch 'generate_docs'

Conflicts:
	liquibase-core/src/main/java/liquibase/structure/core/Column.java
Be more conservative with regular expressions.

Starting with a non-greedy universal match causes Java's regular expression
engine to try to match zero characters followed by the rest of the pattern,
then 1 character followed by the rest of the pattern, and so on until it finds
a match. Since comments must appear at the _end_ of input, this ensures that
the regex engine does a maximal amount of work before eliminating a comment.
For queries of a "reasonable" size, this isn't an issue, but a 10 or 20
kilocharacter query is large enough to cause comment removal to take over a
second.

Since the replacement removes the trailing part of the match outright, I've
rewritten the filter regexes to do so directly, rather than by replacing the
trailing part with the preceding universal group, and removed the universal
group match. This permits the regex engine to skip from whitespace to
whitespace without evaluating all the intervening bytes, and avoids
backtracking entirely.

This bit my day job, in real life, on queries that insert entire PNG images
via hex-encoded strings. While this is an unreasonable query, it's not an
_unrealistic_ query. We worked around the problem by disabling stripComments,
but fixing the regex will improve overall performance.
fixed configuration fail of maven goal liquibase:diff. without referenceServer, configured valued of referenceUsername and referencePassword in pom.xml always ignored.
Merge branch 'master' of https://github.com/frederikcolardyn/liquibase into frederikcolardyn-master
Pulled cassandra support into separate repository
Merge pull request #109 from ojacobson/stripComments-regex-performance

Be more conservative with regular expressions in stripComments.