Add support for ALTER [ object ] IF EXISTS

Prevent NPE in IndexCondition.toString() that may arise from debugging

# Conflicts:
#	h2/src/main/org/h2/res/help.csv

Typo in mvstore file format example.

Also switching 5 and tree, assuming that effectively, page 2 is replaced with a link to page 5, my understanding of log structured storage.

Ignore database resources that are created while running tests

Maven Build

integrated some changes from gansai, fixed table syntax

- Downloaded H2.jar (off maven) and unziped data.zip and verified we are including all the same resources
- Removed the use of maven-exec-plugin as it was wonky and wrote a bridge class to call TestAll via Junit with "fats" arg.