* Create LexicalModelPackageProcessor to handle lexical model packages
* Cleanup PackagePrcessor so less utility methods unzip/parse
* Update FileUtils to handle .model.kmp extension
Fixes#819
* If package version undefined, use "1.0"
* Keyman Developer won't allow undefined package name, but just in case return package ID from the filename
* Check for null before String.toLowerCase()
* Added package processor test for undefined version
For keyboards installed via keyboard packages, use the welcome.htm if it exists for keyboard information
- Update PackageProcessorTest to include CustomHelpLink info
- Renamed Welcome.htm to welcome.htm in test_resources/**/gff_amh_7_test_json.kmp.
- Modify kmp.json to have package versions 1.4 and 1.5.
- also made exception string more descriptive when JSON object doesn't contain a valid "options" object
