closes #303
* add std.buf_map.BufMap * add std.buf_set.BufSet * add std.mem.split * zig build system improvements (See #204) - automatically parses NIX_CFLAGS_COMPILE and NIX_LDFLAGS - add builder.addCIncludePath - add builder.addRPath - add builder.addLibPath - add exe.linkLibrary
closes #300