Change rpc_set_context_args to nfs_set_context_args and make it static

It only makes sense to pass url arguments to an nfs URL and thus a nfs context.
While some arguments may apply to the underlying raw rpc context (uid, gid,
tcp settings etc) some future arguments may need to apply to the nfs context
instead, such as selecting nfs version, whether or not to force sync writes
etc.
Change rpc_mount_* to rpc_mount3_* and make it explicit which version of
the protocol we are using.
Fix some compiler warnings and bugs

Add missing %s to two example programs and fix incorrect argument to
rpc_nfs3_fsinfo_async()
Create SOCURRENT/SOREVISION/SOAGE in lib/Makefile.am
Merge pull request #44 from plieven/master

fix 3 flaws detected by valgrind and bump version to intermediate version
Change all calls to rpc_nfs_fsinfo to rpc_nfs3_fsinfo
Change all calls to rpc_nfs_fsstat to rpc_nfs3_fsstat
Change rpc_nfs_setattr to rpc_nfs3_setattr
Change rpc_nfs_commit to rpc_nfs3_commit
Change rpc_nfs_mkdir to rpc_nfs3_mkdir
Change rpc_nfs_rmdir to rpc_nfs3_rmdir
Change rpc_nfs_create to rpc_nfs3_create
Change rpc_nfs_remove to rpc_nfs3_remove
Change rpc_nfs_mknod to rpc_nfs3_mknod
Change rpc_nfs_rename to rpc_nfs3_rename
Chane rpc_nfs_link to rpc_nfs3_link
Change rpc_nfs_symlink to rpc_nfs3_symlink
Change rpc_nfs_readlink to rpc_nfs3_readlink
Change rpc_nfs_readdir to rpc_nfs3_readir
Change rpc_nfs_readdirplus to rpc_nfs3_readdirplus