Add a Light colored Theme

[GrazianoCapelli]

A dark theme is a Nightmare to use on bright Environments.
I propose to implement a light Theme to improve the readability in these conditions.
The user should have the possibility to switch between light and dark Theme during the usage.

We should start here with a UI mockup.

[GrazianoCapelli]

These days I have some free time, and I chosen to move on with this issue (one of the most requested).
I'm adjusting the style references in order to get ready to implement multiple Themes.
As a start, to test the code, I started to implement the following Theme:

First tests show a good readability even in sunlight.
Suggestion and ideas are really appreciated, specially about the Tracklist's Cards!

[GrazianoCapelli]

With the commit 5fbcc1b the code and the Styles are ready for the implementation of the second Theme.

A draft of Styles and Colors (used for coding and test the Light Theme) are included.
if someone wants to test the Light Theme it and to play with the Light Color Scheme, he can easily enable it by opening AndroidManifest.xml and modifying the following two android:theme lines:

<application
    ...
    android:theme="@style/MyMaterialTheme_Light"
    ...
    <activity android:name=".SettingsActivity"
        android:theme="@style/MySettingsTheme_Light"
        ...
    </activity>
    ...
</application>

The next phase consists on the implementation of the Preference and the code for the run-time switch.
This is - of course - a good time to post here Suggestions, Mock-ups and ideas!
For example, the tracklist now is like the image below:

It needs yet some care!

[GrazianoCapelli]

A SwitchPreference has been added (Light colored Theme).
Now the theme can be changed during the App usage:

It's time to focus on the Tracklist, in order to find a good Design.

[GrazianoCapelli]

Tracklist after the last commit:

It can surely be better, but it is acceptable for me as first instance.
We can continue the test phase.
Of course ideas, mock-ups, suggestions are welcome!

[GrazianoCapelli]

Tracklist refined.
For me is quite good, also for the release.

I'm not 100% sure about the colour of the selected tracks...

[GrazianoCapelli]

After some commits, I think we reached a good result with the Light Theme.
We pushed the 3 Strings related to the Setting on Crowdin.
We chosen to implement a ListPreference instead of a Switch because in a future release we can easily add the possibility to follow the System Settings.

If You have any Suggestion, please consider as a start the Screenshot here below: