Release v0.26.0

[jasonpaulos]

Update changelog and setup.py to prepare for version 0.26.0 release.

[jannotti]

Weren't there two extra fields that got added because we forgot them from v9?

[jasonpaulos]

@jannotti let me know if I have this right: v9 didn't introduce any new fields, but v10 introduced global AssetCreateMinBalance and global AssetOptInMinBalance, which were developed some time ago (and of course the more recent global GenesisHash)

[jannotti]

Sorry, it was v6. These were in your v10 PR, so I figured they should be mentioned here.

:any:Global.opcode_budget() :code:TealType.uint64 6 The remaining cost that can be spent by opcodes in this program
:any:Global.caller_app_id() :code:TealType.uint64 6 The ID of the application that called the current application, or zero. Application mode only
:any:Global.caller_app_address() :code:TealType.bytes 6 32 byte address of the application that called the current application, or the zero address. Application mode only.

[jasonpaulos]

Oh those were just missing from the docs. They've still been functional