Resize line sizes and widths dynamically in test/line_style_docs

Resize the window to see the effect: line sizes increase with the box
size and become wider depending on the box size. Minimal line width
of the "wide" lines has been changed from 4 to 5, maximal width is
now 9. Distinct widths are { 5, 7, 8, 9 }.

Note: the default (thin) line width is now 1 rather than 0 since the
  default 0 may render badly.

Screenshot in documentation has been updated.

1 files changed, 0 insertions, 0 deletions

diff --git a/documentation/src/fl_line_style.png b/documentation/src/fl_line_style.png
index 2e0b29cdb..eab01492c 100644
--- a/documentation/src/fl_line_style.png
+++ b/documentation/src/fl_line_style.png