Adds xdr.f90 to provide a module reading and writing trr files

libxdrfile.a is needed.

also adds test_xdr.f90 and modified utility.f90
Adds the modified xdrfile library which reads double precision...

data without doing any single-double conversion in the middle.

The original xdrfile-1.1.1 can be obtained here:
http://www.gromacs.org/Downloads

There files are modified, where some declarations of float variables
are changed to double:
xdrfile.h
xdrfile_trr.h
xdrfile_trr.c
xdr.f90 is modified to read double precision data directly...

without any precision conversion
Removes redundant double to double conversion in xdr.f90
Merge branch 'xdr'

With xdr module we can now read trr files directly
oneTwoDecompose.f90 now uses xdr module to read trr files directly

The UI is the same.
The relevant atoms to be read must be consecutive from the beginning
in each frame of the trajectory.
Updates Makefile.ifort to compile xdr module and oneTwoDecompose
Uses -heap-arrays to avoid stack overflow for ifort

Also uses -fmax-stack-var-size explicitly with the default value 32768
for gfortran.
Uses character(len=1) for C and Fortran interoperability...

in utility.f90 and xdr.f90

It is the STANDARD
Merge branch 'xdr'
Changes the DIR naming convention in Makefile

Removes the tail slash
Adds an unfinished top.f90 which reads and parses the top files
Continue writing top.f90 to parse the top files
Adds count_record_in_string() in utility.f90
top.f90 is finished

atom mass and charge in top files can be read if they are
written in the [ atom ] records under [ moleculetype ]

Reading [ atomtype ] is not implemented