Merge tag 'v1.8.1'

1.8.1
Convert principalId to String
Add more check on principalId
typo
Merge pull request #246 from haio/master

Convert principalId to String
Ensure roleId and principalId to be string in Role#isInRole
Merge pull request #247 from haio/master

Ensure roleId and principalId to be string in Role#isInRole
Fix client-server example
Fix bug in User#resetPassword
Add homepage to package.json
Merge pull request #252 from haio/master

Fix bug in User#resetPassword
Move content from wiki on LB modules.
Update README.md
Update README.md
Update README.md
Update README.md
Update README.md

removed mobile backend to generalize LB
Update README.md

tweaked opening description again
Removed docs/api-datasource.md 

since it's covered in Juggler JSDoc.
Remove docs/api-geopoint.md from docs