RFC: simplifications and suggestions on open/accept limits.

In a separate email thread, Gert-Jaap Glasbergen is discussing the use of millisatoshis as the smallest fraction in Lightning Network. Rusty Russell argues that not using millisatoshis would render the network inoperable since fees often fall below the sub-satoshi level. However, Gert-Jaap feels that it's important to allow the freedom to choose and respect the confines of the layer being built upon. He proposes conducting further analysis on the consequences of allowing this choice and coming up with a proposal to add support for it. Ultimately, Gert-Jaap seeks to achieve the freedom of choice without negatively impacting other clients or users that decide to accept some level of trust.