There were a number of compiler warnings:
1. int16_t to uint8_t in recon_intra.c;
2. double to float conversions in psnrhvs.c
3. intptr_t to int in quantize.c
4. size_t to int32_t in decoder.c

Change-Id: Id95423b17779dcfa6cf39d9a90fe8cb8b910f5df