Renames currentVersion to currentValue, newVersion to newValue, newVersionMajor to newMajor, and newVersionMinor to newMinor.

Rewrite of dependency extraction, particularly for npm. Paves way for easier addition of new package managers.

Closes #1882

This PR refactors `branchName`, `commitMessage` and `prTitle` so that they are more easily editable and hopefully more understandable. By breaking each up into subsections, users can modify one part without needing to copy/paste the entire string.

Directly editing any of these fields will now be deprecated and a warning issued.

Adds proper enforcement of branch name rules.

Fixes #1724

Closes #1652

This reverts commit dd26a018.

Refactors all instances of .concat() to use array spread operators instead

Closes #1459

This PR adds the capability to renovate more than one base branch at a time. For instance, a project may have their released `3.x` version on `master`, while an upcoming `4.x` is being prepared using branch `next`. `4.x` might have a quite different set of dependencies (e.g. some removed or some added) so it's not appropriate to only target `master` and keep rebasing, as it will get messy. Instead, it's necessary to target both `master` and `next` to keep both updated.

Closes #1279

By stripping ‘types/ from the branch name, package x and @types/x then become automatically combined in the same PR. We then massage it a little to ensure the decription for the non-types package is used, and a note added saying that types is included.

Closes #1365

This makes the onboarding PR easier to understand by putting pin first, then minor, then major.

Repository logic code has been rearranged for better logic and file separation.

Closes #654