Use dynamic memory for all strings

[GoogleCodeExporter]

Currently a lot of strings are defined with statically allocated memory (using 
some predefined constants, like MAX_PARAGRAPH). More robust implementation 
should dynamically allocate memory when needed. This should, in particular, 
remove any limits on the size of input filenames, etc.

(Some of) the function to perform this task are already available in io.c - 
dyn_sprintf and rea_sprintf. The most hard part is probably that of LogError, 
etc.

Original issue reported on code.google.com by yurkin on 20 May 2012 at 3:55