Replace appconfig.json with more robust config language.

 You can
  - log messages with 'log message' command
  - include other configs with 'inclide path' (Note, path is relative to the file it is included from)
  - define parameters with 'name = value'

  Messages, paths and parameter values may contain references to variables in form of ${var}
  where var can be
    - parameter defined previously
    - java system property
    - OS environment variable
Allow '=' in values
URLs are file paths actually
Allow to read configs from classpath resourcesc
Additionally let override configs in context.xml
under sources
config pointer
Configs are now read from .conf files
fix tests
Cache reflection info
Allow interceptors to handle exceptions