Added TOC. Minor tweak to @MirrorsUsed section.
TOC fix
More info on Running the Sample App
fix typo
Using constant rather than fields
Use dart idioms

The tutorial should use dart idioms
fix le
Updated from previous chapter (PR #16 and #17)
fix CS
tooltip should not be public
Propagate #16 and #17 updates
Propagate #16 and #17 updates
Merge pull request #15 from vicb/patch-1

Using constants rather than fields
Merge pull request #17 from vicb/patch-3

Use dart idioms
Merge pull request #18 from vicb/patch-4

Updated from previous chapter (PR #16 and #17)
Merge pull request #19 from vicb/patch-5

tooltip should not be public
Merge pull request #22 from vicb/patch-8

Propagate #16 and #17 updates
Merge pull request #23 from vicb/patch-9

Propagate #16 and #17 updates
[Tooltip] remove unneeded member node
Merge pull request #24 from vicb/tooltip

[Tooltip] remove unneeded member node