Update README, repair symbol links and simplify license headers (#498)

* [chores] update README to new ink! 3.0 syntax * [*] update all broken LICENSE and README.md symbolic links * [*] update all license headers Also be more strict about their dates: 2018-2020 for all

Update README, repair symbol links and simplify license headers (#498)
* [chores] update README to new ink! 3.0 syntax * [*] update all broken LICENSE and README.md symbolic links * [*] update all license headers Also be more strict about their dates: 2018-2020 for all
702b4d36 · Hero Bird · GitHub · 31276d89 · 702b4d36 · 702b4d36
Unverified Commit 702b4d36 authored Sep 30, 2020 by Hero Bird Committed by GitHub Sep 30, 2020
--- a/crates/lang/macro/src/lib.rs
+++ b/crates/lang/macro/src/lib.rs
--- a/crates/lang/macro/src/trait_def.rs
+++ b/crates/lang/macro/src/trait_def.rs
--- a/crates/lang/macro/tests/compile_tests.rs
+++ b/crates/lang/macro/tests/compile_tests.rs
--- a/crates/lang/src/cross_calling.rs
+++ b/crates/lang/src/cross_calling.rs
--- a/crates/lang/src/env_access.rs
+++ b/crates/lang/src/env_access.rs
--- a/crates/lang/src/error.rs
+++ b/crates/lang/src/error.rs
--- a/crates/lang/src/lib.rs
+++ b/crates/lang/src/lib.rs
--- a/crates/metadata/LICENSE
+++ b/crates/metadata/LICENSE
--- a/crates/metadata/README.md
+++ b/crates/metadata/README.md
--- a/crates/metadata/src/lib.rs
+++ b/crates/metadata/src/lib.rs
--- a/crates/metadata/src/specs.rs
+++ b/crates/metadata/src/specs.rs
--- a/crates/metadata/src/tests.rs
+++ b/crates/metadata/src/tests.rs
--- a/crates/prelude/LICENSE
+++ b/crates/prelude/LICENSE
--- a/crates/prelude/README.md
+++ b/crates/prelude/README.md
--- a/crates/prelude/lib.rs
+++ b/crates/prelude/lib.rs
--- a/crates/primitives/LICENSE
+++ b/crates/primitives/LICENSE
--- a/crates/primitives/README.md
+++ b/crates/primitives/README.md
--- a/crates/primitives/src/key_ptr.rs
+++ b/crates/primitives/src/key_ptr.rs
--- a/crates/primitives/src/lib.rs
+++ b/crates/primitives/src/lib.rs
--- a/examples/delegator/accumulator/lib.rs
+++ b/examples/delegator/accumulator/lib.rs