Change. Easy ctor and `setopt` method could use table to set multiple options.

```Lua
c = curl.easy{
  url = 'http://example.com',
  [curl.OPT_VERBOSE] = true,
}
```
Change. Easy/Share/Multi allow set multiple options at once.
Change. Write callback can return any true value (except numbers).
For example in Lua 5.2 file:write method returns `self`.

``` Lua
function write(str)
  return #str - 1 -- this is error (number less than #str)
end

function write(str)
  return {} -- this is pass
end
```
Add. easy escape test.
Fix. Reset options will also reset value in storage.

```Lua
-- Fixed
e:setopt_httppost(curl.form())
e:setopt_httppost(curl.form())
-- `e` store 2 form object and the will alive until `e` is alive.
```
Fix. Use incorrect storage for values.
Merge branch 'master' of https://github.com/moteus/lua-lcurl