Skip and limit feature

[piglovesyou]

Right now this API is in my mind. SyncedDB has a nice and simple syntax to express IDBKeyRange so we can expand it for skip and offset (and filter either in the future, probably).

houses.byStreet.query({
  gt: 'Somewhere 2',
  lte: 'Somewhere 4',
  skip: 20, // <- New API
  limit: 10 // <- New API
})

• I also came up with method chaining type of API but I prefer above one, because:
  1. SyncedDB does not contain such API design of method chaining for now
  2. Function call for syntax sugar sounds slow for me
• sdbIndex.inRange can be deprecated in the case
• .query() will be keeping users away from touching IDBCursor directly
  • So it may need more options for doing equivalently to what IDBCursor can do.

[piglovesyou]

@paldepind I think this topic will interest you as you mentioned in the list.

[piglovesyou]

I changed my mind, using inRange as a method name just makes sense

[piglovesyou]

I force-removed the merged commit and rebased these commits
2586220 b28e0da 2bb9d8f 18d2c30