major refactor to wrap retieval of macros all around ISymbianBuildContext, to avoid need to access internal apis. Added getTargetTypeMacro(String targettype), List<IDefine> getMetadataMacros(), List<IDefine> getBuildMacros().

bin.includes = META-INF/,\
               xmlunit1.0.jar,\
               tools/,\
               testsupport.jar
jars.compile.order = testsupport.jar
source.testsupport.jar = src/
output.testsupport.jar = bin/