Health endpoint interface
Catalog interface reduced: removed two version of service func (with and without tag)
KV endpoint: keys func accepting prefix and separator renamed to sub_keys
Default server address changed from localhost to 127.0.0.1, because localhost may not work
CheckStatus::Failed renamed to Critical. Methods to simple update check status added
sub_keys renamed to subKeys for naming consistency
Comments added
Health endpoint implemented (WIP, no tests yet)
Small code style change
Agent interface simplified
TODO updated
Merge branch 'health' of github.com:oliora/ppconsul into health

Conflicts:
	include/ppconsul/health.h
Small error in build script fixed
Merge branch 'health'
Merge branch 'master' of github.com:oliora/ppconsul

Conflicts:
	TODO.txt