MUONTPAR: fix test failures with static build and tidy up code

[FreddieAkeroyd]

The muontpar system tests fail with the static EPICS build, error is Write access denied for PV TE:SPARE53:MUONTPAR_01:SAVE_FILE but this is likely due to an earlier fault.

[FreddieAkeroyd]

Couple of questions:

• newFileWarning is only set on file not found and not other file errors, is that correct?
• getline is used to read lines in a file, then all lines are concatenated together to store in single char array - could the file just be directly read into the char array?

[rerpha]

@FreddieAkeroyd am i OK to review this?

[FreddieAkeroyd]

@rerpha yes - and please comment on questions above too

[rerpha]

newFileWarning is only set on file not found and not other file errors, is that correct?

Just trying to think which other errors should indicate that the writer is going to make a new file. if it can't load a file it shouldn't overwrite it I don't think?

getline is used to read lines in a file, then all lines are concatenated together to store in single char array - could the file just be directly read into the char array?

possibly - I think Isaac may have done this for the CSS to show newlines but i'm not certain - if it works OK reading directly in we could do that instead and I think that simplifies the logic a fair bit?