Update json parser in gbuild-to-ide

Simplified parser and added the missing json elements:
ASMOBJECTS
CFLAGS
CFLAGSAPPEND
CXXFLAGS
CXXFLAGSAPPEND
CXXOBJECTS
DEFS
GENCOBJECTS
GENCXXOBJECTS
ILIBTARGET
INCLUDE
LINKED_LIBS
LINKED_STATIC_LIBS
LINKTARGET
MAKEFILE
OBJCFLAGS
OBJCFLAGSAPPEND
OBJCOBJECTS
OBJCXXFLAGS
OBJCXXFLAGSAPPEND
OBJCXXOBJECTS
YACCOBJECTS

This patch should not affect the different generators

Change-Id: I74795880d7d34868d61ef73859bda0aedc8b2e28