[#1753] Remove ILBC code and disable it by default in the configure

sflphone-common/libs/pjproject/aconfigure

sflphone-common/libs/pjproject/aconfigure.ac

...ne-common/libs/pjproject/third_party/ilbc/FrameClassify.c

...ne-common/libs/pjproject/third_party/ilbc/FrameClassify.h

sflphone-common/libs/pjproject/third_party/ilbc/LPCdecode.c

sflphone-common/libs/pjproject/third_party/ilbc/LPCdecode.h

sflphone-common/libs/pjproject/third_party/ilbc/LPCencode.c

sflphone-common/libs/pjproject/third_party/ilbc/LPCencode.h

...-common/libs/pjproject/third_party/ilbc/StateConstructW.c

...-common/libs/pjproject/third_party/ilbc/StateConstructW.h

...one-common/libs/pjproject/third_party/ilbc/StateSearchW.c

...one-common/libs/pjproject/third_party/ilbc/StateSearchW.h

sflphone-common/libs/pjproject/third_party/ilbc/anaFilter.c

sflphone-common/libs/pjproject/third_party/ilbc/anaFilter.h

sflphone-common/libs/pjproject/third_party/ilbc/constants.c

sflphone-common/libs/pjproject/third_party/ilbc/constants.h

sflphone-common/libs/pjproject/third_party/ilbc/createCB.c

sflphone-common/libs/pjproject/third_party/ilbc/createCB.h

sflphone-common/libs/pjproject/third_party/ilbc/doCPLC.c

sflphone-common/libs/pjproject/third_party/ilbc/doCPLC.h