etc/cshrc: allow option setting for option software to be specified in ~/OpenFOAM/???/apps/<application>/cshrc

etc/bashrc: allow option setting for option software to be specified in ~/OpenFOAM/???/apps/<application>/bashrc

Squashed merge of particleInteractions up to
commit e7cb5bcf0315c359539ef1e715e1d51991343391

reporting.

Making sixDoFRigidBodyMotionConstraints less verbose by default, now
requires debug switch to be set.

- change from 'kde-open %f' to the desktop-agnostic 'firefox %f' as
  the default document browser.

- this provides a means to temporarily override the default settings
  and/or the prefs.{csh,sh} settings.

  bash:
      name=       -> unset name
      name=value  -> export name=value

  csh:
      name=       -> unsetenv name
      name=value  -> setenv name value

  eg,
      . <WM_PROJECT_DIR>/etc/bashrc WM_COMPILER=Gcc45 WM_MPLIB=
  to use gcc 4.5 and the default mplib

BUG: syntax error in settings.sh

Otherwise all $PATH will pick up the local one which will not be synchronised with $path

COMP: drop gcc-4.2 settings

- the path is accesible either way, but use setenv for consistency with
  other environment variables. It also simplifies foamCleanPath again.

BUG: compilerInstall was getting overwritten in settings.{csh,sh}

non-numeric (eg, a git or cvs version).

- place the onus on the user to provide the correct ParaView_MAJOR in
  these situations.

STYLE: Drop support for cmake older than 2.6.4 (installed in 3rdParty)