Modify examples to be dedicated crates

[farcaller]

As a followup to #330, we need to refactor all the examples to be dedicated crates. This also shows how hard zinc is to use for external users. I'd expect a zinc app to be just one more crate. It is unreasonable to expect the users to download zinc source and add a new "example" entry.

• [x] blink in #318
• [x] blink_k20
• [x] blink_k20_isr
• [x] blink_lpc17xx
• [x] blink_pt
• [x] blink_stm32f4
• [x] blink_stm32l1
• [x] blink_tiva_c
• [x] bluenrg_stm32l1
• [x] dht22
• [x] empty
• [x] lcd_tiva_c
• [x] uart
• [x] uart_tiva_c
• [x] usart_stm32l1

[mcoffin]

Do the concepts from posborne/zinc-example-lpc17xx and the wiki not work anymore?

[farcaller]

they do. The bundled examples are broken though.

[mcoffin]

It is unreasonable to expect the users to download zinc source and add a new "example" entry.

Ah I was just confused by this sentence.

[farcaller]

Right. I forgot about that wiki page when I was writing it.

[farcaller]

Landed all in #318.