* use Parrot_stat_info_intval(..., STAT_FILESIZE) in embed.c:Parrot_readbc() to obtain the PBC file size [1]
* convert all IO Read layer functions to return a STRING* [2]
* toss PIO_read() interface, PIO_reads() is used
* fix the C<readline> opcode, which is actually unusable now for reading files containing more then a few lines.
The returned string gets malloc(3)ed. PObj_external_FLAG|PObj_sysmem_FLAG is set, so that the memory gets freed during DOD.
Comments welcome, leo
[1] might break platforms that lack mmap as well as a stat implementation in config/gen/platforms/*
[2] same signature as Recv()
