ASN1 message from S1AP TS 36.413-8a0

To successfully parse messages, the asn1c util should be patched with the patch provided (asn1cpatch.p0).
To do so: 
0) create asn1c directory
1) Get the last revision of asn1c: svn co https://github.com/vlm/asn1c/trunk  asn1c -r 1516

2) Go to asn1c directory
3) patch -p0 < ../asn1cpatch.p0
4) ./configure
5) make
6) make install

Aligned PER support is now included when parsing and generating asn1 code.

To generate S1AP ASN1 descriptions:
Files are automatically generated when changes are made on ASN1 files via Make build system.
