string with float-likes fail

[alexhallam]

I had a column entry with the following entry in my csv and the program failed.
2/ 2.5 Gallon

The error was

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ParseFloatError { kind: Invalid }', /home/ubuntu/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/tidy-viewer-0.0.5/src/datatype.rs:160:50
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

FWIW

96/3 Oz does not fail. So it must be the decimal in the string