Type conversion warnings

[sagamusix]

Compiling LuaCppInteface with MSVC10 currently yields some type conversion warnings which should be silenced using static_casts for a clean compile:

1>luacppinterface\luatypetemplates.h(134): warning C4244: 'initializing' : conversion from 'lua_Integer' to 'int8_t', possible loss of data
1>luacppinterface\luatypetemplates.h(135): warning C4244: 'initializing' : conversion from 'lua_Integer' to 'int16_t', possible loss of data
1>luacppinterface\luatypetemplates.h(136): warning C4244: 'initializing' : conversion from 'lua_Integer' to 'int32_t', possible loss of data
1>luacppinterface\luatypetemplates.h(139): warning C4244: 'initializing' : conversion from 'lua_Unsigned' to 'uint8_t', possible loss of data
1>luacppinterface\luatypetemplates.h(140): warning C4244: 'initializing' : conversion from 'lua_Unsigned' to 'uint16_t', possible loss of data
1>luacppinterface\luatypetemplates.h(141): warning C4244: 'initializing' : conversion from 'lua_Unsigned' to 'uint32_t', possible loss of data
1>luacppinterface\luatypetemplates.h(144): warning C4244: 'initializing' : conversion from 'lua_Number' to 'float', possible loss of data
1>luacppinterface\luatable.cpp(59): warning C4244: 'initializing' : conversion from 'lua_Integer' to 'int', possible loss of data