Refactor paths(with tests) and bulk operations

[gurgalex]

Closes #48 cc: @Davejkane

why the refactor of paths?

Making the indexes and images fields private forces the user of access methods which at least make the caller consider the possibility of no images being present.

With private fields, removing an image must be done by calling a method which does the proper manipulations for the user.

Some methods now can limit how much mutable access (if at all) is given to the images vec. For instance, sorting the vector can do everything except that which alters its length. Some areas only need read access, so no need to give the ability to replace the whole vec outright. A dedicated reload_imags method is provided for this, which always makes sure the current image index is not larger than the last element's index.

private fields seemed to aid in writing tests as well.

MultiNormal mode

Typing numbers on either the numpad or keyboard while in Normal mode will now switch to MultiNormal mode. This allows for performing many repetitions of Normal actions, but in bulk, like jumping 10 images ahead.

Concerns with MultiNormal implementation

• Lots of code duplication between handling of actions of MultiNormal and Normal mode. Any ideas for somewhat merging the two modes?

• Should actions that can only be performed once (like toggling fullscreen) be allowed as actions in MultiNormal mode. Example 22f would only toggle the state of fullscreen once.

• Infobar display of times to repeat. Should the numbers be on the right like vim?

Small changes

• Made zooming in and out undo each other (*1.1 and /1.1)
• Removed duplication of process_action. It is present only once for each mode, instead of needing duplication on every keypress/text match.

[NickHackman]

@gurgalex Great work! Code review inc...

But first, initial thoughts: Ideally we follow Vim and put the numerical input on the right side of the infobar, since knowing your current index or image would impact your action. Also this is a really big PR, in the future breaking it up would be better in my personal opinion.

[gurgalex]

@Davejkane I currently have the . (dot/period) presses only perform the last non-dot pressed action. 2jand then . would perform the same operation 2j 2. would perform 2j 3. would perform 3j

Did you want the dot presses to multiply as well? Example 2j last action: 2j . would perform 2j 2. would perform 4j 2. again would perform 8j . would now perform 8j

[gurgalex]

@Davejkane I believe all current concerns are addressed.

[Davejkane]

I just checked with vim and it appears that the way you're doing it, without multiplication is correct. I'll try to get around to code review today.