Add colors and erasors

[Eczbek]

• Color structure
• Presets of basic colors
• fg function to set foreground
• bg function to set background
• colors.cpp example
• Erasors:
  • clear_screen
  • clear_screen_until
  • clear_screen_from
  • clear_line
  • clear_line_until
  • clear_line_from
• Removed detail::die
• Added and removed some inclusions

[Ttibsi]

Can you add the example to build.sh as well please?

[Eczbek]

I think the std::flushes are unnecessary

[Ttibsi]

--- a/rawterm.h
+++ b/rawterm.h
@@ -137,9 +137,9 @@ namespace rawterm {
         static const std::unordered_set<char> asciiLetters{
             '\x31', '\x32', '\x33', '\x34', '\x35', '\x36', '\x37', '\x38',
             '\x39', '\x41', '\x42', '\x43', '\x44', '\x45', '\x46', '\x47',
-            '\x48', '\x49', '\x4A', '\x4B', '\x4C', '\x4D', '\x4E', /* '\x4F', */
+            '\x48', '\x49', '\x4A', '\x4B', '\x4C', '\x4D', '\x4E', '\x4F',
             '\x50', '\x51', '\x52', '\x53', '\x54', '\x55', '\x56', '\x57',
-            '\x58', '\x59', '\x5A', '\x61', '\x62', '\x63', '\x66', '\x67',
+            '\x58', '\x59', '\x5A', '\x61', '\x62', '\x63', '\x64', '\x65',
             '\x66', '\x67', '\x68', '\x69', '\x6A', '\x6B', '\x6C', '\x6D',
             '\x6E', '\x6F', '\x70', '\x71', '\x72', '\x73', '\x76', '\x77',
             '\x76', '\x77', '\x78', '\x79', '\x7A'};

Can we make the above change please - some alt_l+characters weren't working.

Note that the uses of std::flush were found to be needed because at least on move_cursor(), I've found that the cursors weren't moving without flushing those codes through. I'm not sure what exactly was causing it, but I needed that to work

[Ttibsi]

Git messing up here, had no intention to close this PR -- see #20