- Autodetect SDK by environment variable EPOCROOT and qt directory
below.
- Environment::appendOrSet/prependOrSet: Avoid duplicate entries
- Rename toolchain enumeration value
- Adapt S60ToolChainMixin to new GnuPoc setup, provide routines for
  all required variables.
- RVCTToolChain: Make RVCT detection smarter (Check for RVCT<v1><v2>BIN
  variable). Set all required variables in case of RVCTToolChain/GnuPoc
- QtVersionManager: Detect toolchain and Qt version properly, make S60
  device run config accept toolchain.
- Modify S60DeviceRunControl to execute 'make sis'
- Modify S60Devices::detectQt...() to check for Qt installed into SDK
  first and symlink as fallback.

 * Rework IBuildParser:
    * Remove name() method.
    * Remove enterDirectory and leaveDirectory signals.
    * Allow chaining of parsers.
 * Rename IBuildParser to IOutputParser.
 * Implement GnuMakeParser.
    * Remove entering/leaving directory related code from all other parsers
    * Move filename fixup heuristic based on entering/leaving directory
      massages from gnumake here from AbstractMakeStep.
 * Add outputParser method to ToolChain: This removes the need to map
   toolchains to BuildParser names in the BuildSteps.
 * Enhance AbstractProcessStep to accept a IOutputParser to parse its output.
 * Remove AbstractMakeStep.
 * Set the appropriate Parsers in all classes deriving from AbstractProcessStep
   and append the ToolChain's parser to the parser chain.
 * Remove BuildParserFactories: There is no more need for them.
 * Remove constants used to identify the BuildParsers.
 * Clean up some names:
    * Replace stdOut with stdOutput.
    * Replace addToTaskWindow with addTask and addToOutputWindow with
      addOutput. Do this wherever it is not yet clear that this will end up
      in the Task/Output window.

Reviewed-by: dt

Factor out the initialization setting up the environment and headers in
the RVCT/GCCE toolchains.
Modify the RunControl to be able to support different package
building/signing processes.

Also makes the code a lot smaller.

It works, except that the code model doesn't get the rvct include
directories and defines yet. And you need to have everything for
rvct set up in your environment.

Passing the Project to the tool chain now. Not quite sure if I like it.