REFACTOR: bump version to 6.0.2
REFACTOR: for pak 0.10
UPGRADE: mpr and minor doc updates
DEV: Permit empty extension for httpAddCache.
REFACTOR: httpLoadConfig

Split into httpInitConfig, httpLoadConfig and httpFinalizeConfig to permit loading multiple json config files.
Change httpAddConfig to take keys for the json file being loaded.
Invoke callbacks after blending json into HttpRoute.config.
Remove HttpRoute mutext (unused)
Change CLIENT_DIR to PUBLIC_DIR in httpRoute. Rename httpAddClientRoute to httpAddPublicRoute.
DEV: Permit null host in GetDefaultRoute.