Separate src/main.js to each panel/functionality with using context

[sanak]

Closes #7

This PR is minimum level of refactoring. Here are some notes.

• Separating mappanel.js and iopanel.js was difficult due to many dependencies, so I gave up to separate those and concatenate it as mapiopanel.js.
• Basically, each <input> control related methods need to be defined in the panel which includes it, but currently, the methods are in most used panel or functionality. (ex. getArgumentValue in geosop.js)
• Move html inside event handler to each panel's inside with addEventListener.

For future, something MVVM? or state management? may solve above problems, but I will think about it, after upgrading OpenLayers.

TODO:

• [x] Currently, all operations are failing in geomToWkt method's geos.GEOSNormalize(geom) line. I need to fix this bug.

[sanak]

Currently, all operations are failing in geomToWkt method's geos.GEOSNormalize(geom) line. I need to fix this bug.

The cause was just geomToWkt syntax error.

Merge this PR with squash.