Changes debug endpoint to /api/v3d

Changes debug endpoint (#8)

The endpoint was changed from /api/debug/v3 to /api/v3d in ICON 2.0

Adds calculated transaction fee in getTransactionResult call

v1.2.1

Updates changelog

Throws Exception when RPC call fails

Merge pull request #5 from iconation/1.2.0

Throws exceptions on RPC errors

Refactors icxToHex and hexToIcx functions

Refactors icxToHex and hexToIcx functions to properly work with big numbers, requires another bcmath php extension and bumps required PHP version to v7.2

Adds changelog and security policy

v1.0.1

Updates changelog

Supports Iconservice, IRC-2 and IISS functions

Merge pull request #4 from iconation/debug_estimate

Estimate step and docs

v0.1.4

Adds new features and unclatters part of code

v0.1.3

Adds helper function to turn decimal ICX value to hex

v0.1.1

Adds isPublicAddress function to Wallet