to capture chars at UART at 250000 baud.

.. and give the hint to try lower values if possible.

MENU_HOLLOW_FRAME for the menu screens and
some pixel shifting to optimize the look with tall fonts. (cn)

To optimise speed.
Costs well invested 128Byte of RAM.

For speeding up font drawing unify font decent.
Tr and Gr have ben the only fonts with a font decent of -2.
Sorry for some, a bit compressd, but hopefully still readeble symbols.

・Add new translation

Add check for Turkish Font before setting better font for graphic displays

Instead of waiting for a single long block, compare the complete block
buffer runtime for the long_move() check.

・Fix memory leak

・Change translation for 16 width LCD

Simply apply enabled settings instead of requiring users to edit
stepper_indirection.cpp

If the stepper ISR takes too long, chars are lost which leads to serial
communication errors like "Line number not +1" or "Wrong checksum". In
worst case, the printer can even do crazy moves.

With this changes, UART interrupts are handled inside the stepper ISR.
This way, no chars should be lost.

At the start of a move, check if the endstops are already triggered.
The 'change' interrupts will not see a change if already triggered.

lcd_update can take so much time that the block buffer gets drained if
there are only short segments. This leads to jerky printer movements for
example in circles and a bad print quality.

This change implements a simple check: Only if the block currently
executed is long enough, run lcd_update.
This also means the printer will not show actual values on the LCD nor
will it respond to buttons pressed. A option that keeps the menu
accessible is also available.
Aditionaly, slow down if a block would be so fast that adding a new
block to the buffer would take more time. In this case, the buffer would
drain until it's empty in worst case.