Fix several more -Wtype-limits warnings (cf. r3759)

Embarrassingly, many seem to be from my 64K sidedefs patch (r3588).

Two remain: one in jsoncpp, which is an embedded upstream library, not
part of Odamex; and another in sv_sqp.cc, which is a comparison against
a version number macro which might not always expand to zero.

Signed-off-by: RjY <rjy@users.sourceforge.net>

git-svn-id: http://odamex.net/svn/root/trunk@3760 b0bcef46-2027-0410-bd56-ab726e9a1d04
We no longer have any NOASM blocks in our source, so remove -DNOASM from our CMakeLists.txt.

git-svn-id: http://odamex.net/svn/root/trunk@3761 b0bcef46-2027-0410-bd56-ab726e9a1d04
Add an easy CMake variable to turn on Address Sanitizer on GCC >= 4.8 and Clang >= 3.1.


git-svn-id: http://odamex.net/svn/root/trunk@3762 b0bcef46-2027-0410-bd56-ab726e9a1d04
Change nameplayer() to use std::strings.  This avoid an out-of-bounds memory access in the original c-string implementation.

git-svn-id: http://odamex.net/svn/root/trunk@3763 b0bcef46-2027-0410-bd56-ab726e9a1d04
nameplayer() now takes a const std::string reference.

git-svn-id: http://odamex.net/svn/root/trunk@3764 b0bcef46-2027-0410-bd56-ab726e9a1d04
Convert userinfo.netname to use a std::string.

git-svn-id: http://odamex.net/svn/root/trunk@3765 b0bcef46-2027-0410-bd56-ab726e9a1d04
userinfo_s -> UserInfo, with default weapon preferences being a static member thereof.

git-svn-id: http://odamex.net/svn/root/trunk@3766 b0bcef46-2027-0410-bd56-ab726e9a1d04