Fault injection for file reads on Linux

Imitates using network file systems under high load. Can be used in 2 ways:

1. Compile to shared library, load with LD_PRELOAD. Control with READFLT_PRECENTAGE environment variable. 0 = no faults, >99 = all faults

2. For more fine grained config: #include into 1 of the sources. Control using ReadFlt global structure:

int percentage - faults per 100 calls int truncPercentage - random EOFs per 100 remaining calls char *prefix - if not NULL, only mess with paths starting with this