Adding theme options

[KristiforMilchev]

Hello Hori,

I hope that you don't mind the changes but i found your package useful and i want to use it in my desktop software. However i found out that the customization options by default were not enough to make it usable for desktop so i extended you package with few more options.

The change list includes the following changes:

• DayCellConfig new config option to style the cells of the calendar it can manipulate the day cell options. i think it's important to have so that people can use it across different color schemes then the default white or black color scheme. It also defines the font size of each cell and allows the user to define a border around the selected field.
• PaletteConfig - extended with the following options

1. boxColor it allows the user to change the default color behind the border of each cell.
2. todayFontColor allows the user to change the default white for the selected date (defaults to the original white)
3. selectedBorder Allows the user to define a border color around the selected date, by default is transparent
4. dayFontColorInMonth changes all font colors for days in the current month
5. dayFontColorNotInMonth changes the font colors for all days outside of the current month

I have some other ideas on how we can improve the package, but i think this is a good start, in the following days i will open few more prs that i am working on but i do believe that we should spent some time to refactor the code and get rid of the functions inside the views as they are really redundant since we already initialize all configs when we call the constructor, i didn't do any refactoring as i think it's your decision but do let me know if you want to go there at some point till then i will try to keep the code style in your format.

let me know if you want me to make any changes in the comments bellow.

Best regards and i hope this gets merged,
Kristifor.

[hori-imuuzak]

Hi. KristiforMilchev

I have reviewed your request.

Thank you for the beneficial changes!

We will merge them.

You may be using a forked library, but we will be sending you an updated patch version of the library from pub.dev.

Thank you!