Change name of test folder to plural
Makes a copy of abundance

It was changing the parameter outside of this object.
Merge branch 'hotfix-synplot-abund' into development
Create folder to store extra resources

Extra resources as files and other stuff must be put here.
Move periodic table
Copy Extra Resources when installing package

This will be copied to `~/.s4/extra_resc/`
Change path to Periodic table

This will be installed on the system.
Remove unnecessary import

It was importing S4 during installation.
Correct path to extra resources

It was badly defined.
Merge branch 'hotfix-periodic-table' into development

Creates a folder to store extra resources. The first one is the periodic
table.