glpk solver implementation, ready to start testing
Merge branch 'kai-branch'
glpk wrapper was added

the glpk wrapper and 2 unit tests were added:
 -  test_glpk_alone - checks if glpk produces the correct output for a
basic LP problem. the idea is to check that glpk alone is working well.
  - test_glpk_against_gurobi - solves the same problem with gurobi and
glpk and checks if the objective function values are the same.
Merge branch 'marta-branch' of github.com:cdanielmachado/framed
code style according to pep8 + glpk instructions

the isntructions to install  python-glpk on Mac OS and linux were added
on the framed/misc folder.
the code previously changed was formatted according to pep8
Added glpk pickle test.
Forgot the changes in glpk_wrapper.py
Merge pull request #10 from cdanielmachado/marta-branch

Merging pull request from Marta to master branch
Merge branch 'master' of github.com:cdanielmachado/framed
Fixed a couple of problems in GlpkSolver
Tried to fix a couple of things in GlpkSolver
fixed glpk row bounds + status mapping

if row lb == ub: the bound is fixed, otherwise it is a double bound;
the glpk status mapping is now completed and both statuses INFEASIBLE
and NOFEASIBLE are mapped into INFEASIBLE
reset objective function after solving the problem
fixed loop that goes through all the objective function coefs
presolve is back
Some updates to the solver interface.
Merge branch 'fix_glpk'
Update the solver interface
Update gurobi wrapper
Fixes in pFBA, lMOMA