Fix - Should not be a space after -i in SEDOPT

[7415963987456321]

Ran into problems when running make and ./test, the sed option -i should not have a space between -i and ''

• Fixes the sed expression in the test and install script
• Alternatively one could also use --in-place=[SUFFIX] instead but I opted to just remove the space

[nickolasburr]

@7415963987456321 Thank you for the contribution and sorry it's taken so long. This works for GNU sed but will break if using BSD sed, which requires the space after -i.