Add an install command

Upgrade* classes renamed Install*
Add a parameter and conditional to control whether an upgrade or new install is performed

Separate --upgradedb (upgrade) or --initdb (new) params for database
Maintains backwards compatibility for now, will probably change to a common argument when the command line args are refactored
Fix test_upgrade.py (UnixUpgrade->UnixInstall)
If Stop caught with non-zero code, print "ERROR:"
Add help text for --initdb and --upgradedb
Change .travis.yml to run separate install and upgrade tests
Check for symlink before downloading

Also rearrange log messages
Modify CreateGeneOntologyTags.py to generate json
Prepend id to the name of the tags.
Fix typo
Add indent
Move CreateGOTags to 'omego convert' command
Merge pull request #36 from manics/server_init

omego install
Merge pull request #40 from joshmoore/tag-update

Modify CreateGeneOntologyTags.py to generate json
Merge 'origin/master' into yaclifw-migration

Conflicts:
	omego/main.py