Clean up the FileReader class and all of the modules that use it.

- Modules which use this class will now have to catch a
  CoreException when opening files if they wish to ignore
  the failed loading of a file.
- m_randquote has been cleaned up massively and the RANDQUOTE
  command has been removed as it was pretty much useless.
Deduplicate RemoveMode() implementations

The default (core) implementation can now remove prefix modes
The modestacker parameter is now mandatory
Simplify user mode removal via ModeHandler::RemoveMode()

The function does not need to be virtual because the core can remove any user mode using the default logic
The optional modestack parameter was always NULL, so remove it
Made the settings for m_blockcaps a per-channel setting instead of config defined.
Moved the current m_blockcaps module to m_blockcaps_compat for networks with 2.0 servers still linked.
Updated config files to reflect the new chmode B setting.
Syntax for mode: +B percent-of-caps:minimum-text-length
Requested in #463
You can now block (~) or ban (*) with m_blockcaps
Kicks my default and in combination with bans.
Same functionality as m_messageflood
Updated helpop files