Small fixes for Examples

[corranwebster]

This PR fixes a couple of small issues found when working with the examples:

• the savage static demo didn't work on Python 3 because the XML writer expected bytes, not str.
• error reporting was broken in the KivaExplorer, and the timing editor was an editable field.

This fixes both issues.

[codecov-io]

Codecov Report

Merging #388 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master     #388   +/-   ##
=======================================
  Coverage   32.73%   32.73%           
=======================================
  Files         206      206           
  Lines       18297    18297           
  Branches     2470     2470           
=======================================
  Hits         5990     5990           
  Misses      11929    11929           
  Partials      378      378

Impacted Files	Coverage Δ
enable/savage/trait_defs/ui/qt4/svg_editor.py	0% <0%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c6e7664...c96cc8a. Read the comment docs.