Add precious qualifier for esp paks
DEPS: Fix assert in mprListToString
FIX: require bit 0.9.0
REFACTOR: Update esp.c error messages
FEATURE: Add package.json

Generate bower.json.
Move version information to package.json.
FEATURE: Prototype session expiry callbacks.

Add httpSetSessionNotify
Add httpSetSessionLink
DEPS: Update ejs, mpr.