Changes on the LP interface

_FixId => LpId
- handling of not common ids // soplex
LpGlpk row and col erase bug fix
- calling lpx_std_basis before simplex
LpSoplex
- added getter functions
- better m4 file
- integration to the tests
- better handling of unsolved lps

c LEMON max flow problem

p max 7 9

n 1 s

n 7 t

a 1 2 3

a 1 3 2

a 1 4 1

a 2 5 3

a 3 5 2

a 3 7 5

a 3 6 3

a 4 6 1

a 5 7 2

a 6 7 4