Minor style fix
Plots: rewrite timetrace and ratetrace plots.

New features:
- New functions: timetrace, ratetrace, timetrace_single, ratetrace_single
- Same functions handle both ALEX and non-ALEX
- Clear and consistent API
- Significant RAM optimization for timetraces

As before:
- Plot rates from burst search or background
- Plot bursts and optional click-on-burst GUI that prints burst info

Note: The old plot functions were deleted so there may be some backward incompatibility.
Plots: small improvements to ratetrace and timetrace
Plots: improve hist_bg_fit
Plots: fix timtetrace scrolling
Plots: fix GUIs in multi-figure plots (manta)
Plot: tentative gui fix (WIP)