some more testing
testing related to issue #4
new function Ancillary.meltingPressure_T
melting pressure of helium
for each decrease of convergence speed, iter_max is increased by one,

fixes #4 (together with melting pressure)
move Boolean "useLineSearch" to the EoS stuff
melting pressure for Butane
melting pressure for Helium
melting pressure for IsoButane
melting pressure for IsoPentane
melting pressure for Pentane
melting pressure for Propane
typo and testing
moved issues to issue tracker,

https://github.com/thorade/HelmholtzMedia/issues?state=open
comments and some minor corrections
:new: function Ancillary.meltingPressure_T
tau cannot be negative,

but this did not solve my problem...
intermediate version: adding linesearching to setState_ps did not solve issue #4,

an example that doesn't converge is included,
why is slope<0 ??
intermediate version: Homeier algorithm

http://dx.doi.org/10.1016/j.cam.2003.12.041
interesting modification of Newton,
but still does not solve issue #4
intermediate version: Darvishi algorithm

http://dx.doi.org/10.1016/j.amc.2006.11.022
interesting modification of Newton,
but still does not solve issue #4