Refactors the escaping function

This is the first step to reduce the memory usage. The escaping function was
changed to: given a string it is capable to compute the amount of bytes that
will be needed to really ecape it.
Optimizes the memory utilization of the @pmFromFile operator

This commint reduce the amount of memory used by the operator @pmFromFile while
loading the configuration. It is expected that @pmFromFile uses less than 68%
of memory that it was using before this optimization.