Integrate the building of nvdaHelper into NVDA's scons files:

Integrate the building of nvdaHelper into NVDA's scons files:
*NVDA's new root sconstruct: declare and export clientDir, sourceLibDir and sourceLibDir64 variables, which can be used by nvdaHelper and client etc.
* Move source/include to include (at NVDA's root). also change all mentions of the path '#../include' to '#/include' in nvdaHelper's sconscript files.
* Move contents of nvdaHelper's site_scons to NVDA's root site_scons
*Move the nvdaHelper dir out of source and in to the root of NVDA.
* Rename nvdaHelper's sconstruct file to sconscript
* nvdaHelper's archBuild_sconscript: Remove the 'install' target, and at the same time no longer collect built targets to make them be required by the install target.
* NVDAHelper's sconscript (previously sconstruct):  no longer create a base environment from which to clone the arch-specific environments, instead Import  the environment called 'env' and clone from that.
*nvdaHelper's sconscript: import clientDir, sourceLibDir and sourceLibDir64, and pass arch-specific variants of these to archBuild_sconscript.
*nvdaHelper's archBuild_ssconscript: do not hardcode libInstallDir and clientInstallDir, instead import them (given by nvdaHelper's sconscript).
* Remove pointless print statements from NVDAHelper scons files
* Move the commandline variable declarations (such as targetArchitectures and logLevel) from nvdaHelper's archBuild_sconscript and in to NVDA's new root sconstruct.
* rename the 'isRelease' commandline variable in NVDA's new root sconstruct to 'release' to be compatible with nvdaHelper -- it uses it in quite a few places.
*NVDAHelper's remote, client and local sconscript files: change all mentions of the path '#interfaces' to '../interfaces' (we can no longer really use # as its now at NVDA's root.
*nvdaHelper's remote/apiHooks.cpp: explicitly include nvdaControllerInternal.h above common/log.h as for some reason now scons is failing to scan more than one level deep for implicit dependencies -- all other files including log.h already did this.
*NVDA's new root sconstruct: no longer build an nvdaHelper archive (its no longer needed)
*NVDA's new root sconstruct: there is now a target called 'client' which will build the nvda controller client archive.

Further notes:
*As dist (portable, installer etc) depends on source, any nvdaHelper related libs / EXEs that should be in source will automatically get built when needed.
*controller client will no longer get built just because the rest of nvdaHelper is built, unless you specifically tell scons to build the 'client' target.