Pyerrors

Added
- `pyerrors` can now deal with replica with different gapsizes.
- String formatting method for `Obs` added.
- `t0` can now be extracted from hadrons files.
- `w0` can now be extracted from openQCD files.
- `pandas` SQL export can now deal with `None` entries in columns with `pyerrors` datatypes.


Fixed
- `dobs` submodule is now correctly imported.
- Bug in merging of `Obs` fixed.
- Bug in `rapidjson` dict output fixed.
- String conversion of `Obs` can now handle special `dvalue`s
- Bug in sfcf name sorting fixed.

Added
- Alternative way of specifying priors in `least_squares` added.
- Correlated fits now also work with priors.
- Lists of `Obs` can now be serialized and deserialized in pandas.to_sql
- `print_config` function for debugging purposes added.
- `Corr.show` can now visualize results of combined fits.

Changed
- Fit routines refactored and simplified.
- sfcf input routines refactored.
- drho is not automatically computed for all windows in the automatic windowing procedure. This change speeds up the `gamma_method` for very long Monte Carlo histories.
- `__slots__` added to `Corr` class.

Added
- The fit module now has a new interface to deal with combined fits.
- `pyerrors` wrapper for matplotlib `errorbar` method added for `Obs` valued lists/arrays.
- roots module can now determine roots of multi parameter `Obs` valued functions.

Fixed
- Bug in treatment of error propagation of non-overlapping configurations fixed.
- `Corr.symmetric` can now deal with `None` entries.
- Fix in `ms5_xsf` input routines.
- Bug in `dobs` output format fixed.

Added
- Alias `gm` for `Obs.gamma_method` added.
- Hotelling t-squared p-value added for correlated fits.
- String conversion of numpy arrays containing `Obs` improved.
- Input routine for xSF measurement program added.

Fixed
- Complex valued `Corr` objects fixed.
- Small bug in `qtop_projection` fixed.
- Bug in `Corr.spaghetti_plot` fixed which appeared in connection with replica separators.

Changed
- Merged `Obs` are no longer filtered as this lead to inconsistent `idl`s in some edge cases. Error estimates are unaffected up to filter precision.

Removed
- Removed the `Obs` attribute `is_merged` as this information was only needed for the filtering. The change results in a ~1.15x speed up in the multiplication of two `Obs`.

Added
- Log-derivatives and symmetric log-effective mass added.
- Covariance for irregular Monte Carlo chains sped up.
- Additional checks in `Corr.GEVP` added.

Fixed
- Bug in `Obs.details` fixed which appeared when tau had zero error.
- Bug in `input.json` export in connection with `numpy.int64` fixed.
- Small bug fixes in `input.openQCD`.

Fixed
- Integrated autocorrelation times are now correctly estimated for gapped irregular Monte Carlo chains.
- The output of `Obs.details` was improved and now contains information about the stepsize in configurations for which the integrated autocorrelation time was estimated.