add encode big number as string option

feature: add option to disable forward slash escaping

Thanks @spacewander for optimization and documentation.

v2.1.0.7rc2

feature: ported to the ARM64 platform by masking off the bits higher …

…than 47-bit in the lightud.

Signed-off-by: Yichun Zhang (agentzh) <agentzh@gmail.com>

bumped version to 2.1.0.6.

bugfix: fixed the C compiler warning "SO C90 forbids mixed declaratio…

…ns and code" on older operating systems.

feature: set cjson.array_mt on decoded JSON arrays.

this can be turned on via cjson.decode_array_with_array_mt(true). off by
default.

Signed-off-by: Yichun Zhang (agentzh) <agentzh@gmail.com>

bugfix: conditionally build luaL_setfuncs() function as the latest Lu…

…aJIT v2.1 already includes it. fixes openresty#21.

travis-ci: added valgrind testing mode as well.