merge p3dfft wrapper with solid_model branch (now contains domain decomposition + bugfix if ny>nz and mpisize>nz)
now really do what I wanted to do in the last commit (merge cof_p3dfft with solid_model branch)
forgot some variable declaration in partial merge
Read insect takeoff parameters from ini file
add parameters added by dmitry to standard parameter file (for sake of completeness)
Remove unused variables to decrease the number of warnings in compilation.
Remove a.out (created on Turing) when calling make clean or make tidy.
Make the f90 files non-executable.
Add parameters to specify runtime backups based on walltime.

truntime is a real specifying the number of hours between runtime backups

wtimemax is a real specifying the max walltime for the program.  Does
a runtime backup before exiting.
Change default walltime limit to 1 year.
Save backup file at end of time-stepping if ibackup==1.

Also fix sphere_restart unit test to match new behaviour.
Fix typo in Makefile and remove redundant compiler flags.
fix yet another lowercase issue (iDoBackup instead of idobackup -> otherwise always default value is used)
remove f77 code from params.f90, plus bugfix: keyword is now *really* in the section, not just after the section keyword
reformat standard parameter file
further improvements in params parser + introduce (len=strlen) wherever found
Merge branch 'master' into solid_model

Conflicts:
	Makefile
	PARAMS_test_fsi.ini
	src/cof_p3dfft.f90
	src/flusi.f90
	src/geometry/add_channel.f90
	src/geometry/hyd/mask_fsi.f90
	src/integrals.f90
	src/params.f90
	src/postprocessing.f90
	src/rhs.f90
	src/runtime_control.f90
	src/time_step.f90
	src/vars.f90