Log Message:
Update to lp_solve_5.5.2.3 and indicate a 64-bit platform for aarch64
Fix isnan() checks to declare main() returning 'int' and use floating
argument to isnan() avoiding recent (gcc 5) compiler noise.

Since last update:
../../.. version 5.5.2.1
- fixed a small error in new and improved MIP_stepOF function to find integer \ 
solutions.

../../.. version 5.5.2.2
- For integer models with semi-cont variables it happened sometimes that a message
  "fillbranches_BB: Inconsistent equal-valued bounds for ..." occured \ 
and that the semi-cont condition
  was not respected.
- New functions added: get_accuracy to get the numeric accuracy after solve.
- New functions added: set_break_numeric_accuracy, get_break_numeric_accuracy to \ 
let lp_solve return ACCURACYERROR
  instead of FEASIBLE when numerical accuracy if worse then the provided values.
  In the past, lp_solve only returned a non-optimal status in case of very \ 
severe numerical instability.
  Now it will return already ACCURACYERROR when it finds a relative inaccuracy \ 
of 5e-7
- When reading a model from the lp-format and important issues are detected such \ 
as already bounds on variables being overruled
  later with for example a bin keyword, this is now reported in the default \ 
verbose level such that this is seen easier.

08/05/16 version 5.5.2.3
- For some models with integer variables, lp_solve did not find the most optimal \ 
solution.