Use un-minified Preact in DEV mode

[thangngoc89]

This is to prevent cryptic stack trace like this

Uncaught TypeError: Cannot read property '_renderedComponent' of undefined
    at visitNonCompositeChildren (eval at ./cli/node_modules/preact/devtools.js (app.925b01a….js:912), <anonymous>:209:16)
    at Object.componentUpdated (eval at ./cli/node_modules/preact/devtools.js (app.925b01a….js:912), <anonymous>:151:4)
    at Object.preact.options.afterUpdate (eval at ./cli/node_modules/preact/devtools.js (app.925b01a….js:912), <anonymous>:237:11)
    at k (eval at ./cli/node_modules/preact/dist/preact.min.js (app.925b01a….js:920), <anonymous>:159:122)
    at i (eval at ./cli/node_modules/preact/dist/preact.min.js (app.925b01a….js:920), <anonymous>:28:16)

[oren]

Does it mean I will know where the error is actually coming from? That's awesome

[thangngoc89]

@oren Not actually. Just the last two lines in the above error (which is from preact's source)

at k (eval at ./cli/node_modules/preact/dist/preact.min.js (app.925b01a….js:920), <anonymous>:159:122)
    at i (eval at ./cli/node_modules/preact/dist/preact.min.js (app.925b01a….js:920), <anonymous>:28:16)