v0.1.3 - Single line files handling

Added full support for single-line files with R1 value only. The second value in the first row can be input as peak intensity, if present. Rest of the file is ignored. Added ability not to fit background or peak to the spectrum, which does not exist in the above case. This modification is handy to work in a consistent way with manually generated R1 values without artificially generating a spectrum for them. Updated about and README.

What's Changed

• Single line by @Baharis in #6

Full Changelog: v0.1.2...v0.1.3