Add support for reading .rdebugrc files in merb -D mode. Runs both ~/.rdebugrc and ./.rdebugrc, in that order, as part of opening the debugger.
Add support for reading .rdebugrc files in merb -D mode. Runs both ~/.rdebugrc and ./.rdebugrc, in that order, as part of opening the debugger.

Based on the code used in the rdebug command, here:
http://github.com/timcharper/ruby-debug/commit/cb28c06d9681bb261fb058c68135fd20529d7780

Signed-off-by: Michael S. Klishin <17b9e1c64588c7fa6419b4d29dc1f4426279ba01@novemberain.com>

merb/merb,wycats/merb,wycats/merb,merb/merb,wycats/merb,wycats/merb,wycats/merb,merb/merb